<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <input type="text" name="username" id="username" value="admin"><br>
    <input type="text" name="password" id="password" value="123456"><br>
    <input type="button" value="提交">
    <button onclick="fun1()" id="zxt">测试</button>



    <script src="../js/jquery-2.1.4.js" type="text/javascript" charset=""></script>
    <script>
        function fun1() {
            $('#username').css('color', 'red');
            $('#password').css('color', 'blue');
            $('#zxt').css('color', 'green');

        }

    </script>
</body>

</html>